On the proposed music for overworld, I would use to describe it as "sunny" and "adventurous". Listening to that makes me feel like "hey what a great day, the sun is shining, birds are chipping;...".
I think that matches with the open space that is our overworld

On farm2.ogg: that sounds so "Crash Bandicoot-y" ! But I don't picture a farm at all with that one...I tend to picture levels of Crash 2 actually

So...great song, but maybe a bit generic? I'm not sure where it could be used?
Also, should we aim at a consistent style of music throughout the game?
EDIT: on how to make it sound more "western": I would take inspiration from Country music, which is quite fast and uses banjo-style sounds. Typically, Ricky Skaggs:
http://www.youtube.com/watch?v=8uIxJFZoCxMViolin is also very important, the rythm is particular and makes us want to follow the beats with our foot on the floor

On the scales, it's generally major scales, and very few variations on the chords used...
Well, no link with what you produced, maybe that's room for a brand new music actually
